Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 18: Poster Monday: 2D Materials 1

O 18.24: Poster

Monday, September 5, 2022, 18:00–20:00, P4

Relaxation, the moiré potential and excited states for twisted TMDC bilayers — •Carl Emil Mørch Nielsen, Miguel da Cruz, Abderrezak Torche, and Gabriel Bester — University of Hamburg, Institute of Physical Chemistry, 22761 Hamburg, Germany

In recent years, the research of transition metal dichalcogenides has amassed much attention due to interesting properties such as strong localisation of excited states. The field of twistronics emerged as twisting provides a new degree of freedom in engineering specific properties. However, the theoretical ab-initio approach shows an immediate challenge to overcome; large systems, where the moiré unit cell may hold thousands of atoms.

In this project, the aim is to theoretically study moiré confined optical excitations in twisted TMD vdW-homo and heterostructures. We have successfully integrated a force-field based method of relaxation using LAMMPS as suggested in a paper by Jain et. al. We have re-parameterized the SW and KC potentials seen in this paper and expanded the parameter set to include all possible bilayer TMD combinations. With these we can accurately model the associated local band gap variation, e.g. the moiré potential, taking into effect both lattice corrugation and atomic reconstruction. Our goal is now to investigate the excited state properties with our group-developed code from first-principles.